The present invention relates generally to digital imaging cameras, and, more particularly, the invention relates to electronic still cameras having a mechanically adjustable sensor for adjusting image focus.
Conventional imaging cameras have long adjusted focus by physically moving a lens in an optical system of the conventional camera. The movement of the lens can be automatic movement driven by a motor, or manual movement under user control. In either case, the lens itself is mechanically moved relative to a film plane. It is well known in the art that as an object comes in from an infinite distance with respect to a lens, a focal plane on which the lens forms a sharp image when correctly focused is moved away from the lens. Thus, to correctly focus the image of an object onto a film plane, the lens is mechanically moved away from the film plane. Analogously, electronic still cameras have provided a similar function where, instead of a film in the film plane, there is an electronic sensor, such as a charge-coupled device ("CCD"), which is in the film plane. A problem with this type of focusing system is that lenses are often interchangeable on a camera, thus making a lens system that is individually moveable and interchangeable very costly. In addition, each lens system that is interchanged onto the camera must have the same functionality, i.e., each must be user adjustable or adapted to be driven by a motor.
Accordingly, it is an object of this invention to provide an electronic still camera that works with statically mounted lenses while optimizing image focus.
It is another object of this invention to provide an electronic still camera that reduces a cost of accessories by reducing an overall cost of interchangeable lens systems for the electronic still camera.
These and other objects of the invention will be obvious and will appear hereinafter.